Scientists in the US who used functional magnetic resonance imaging (f-MRI) scans have found higher-than-average activation of a key structure in the brain's reward circuitry of people experiencing religious thoughts just preceding their peak spiritual feelings.

A study in Denmark had eight years ago first indicated that prayers might stimulate the brain's reward pathway, but the new findings are the first to document spikes in the activity of the structure called the nucleus accumbens.

"The nucleus accumbens is among the most influential structures in the brain's reward system," Jeffrey Anderson, a neurobiologist at the University of Utah who led the study, told The Telegraph. "We believe our observations may explain the deep emotional feelings people experience through religious spiritual experiences."

In their study, Anderson and his colleagues examined f-MRI scans of 12 men and seven women as they performed four tasks, including reading familiar passages from the Book of Mormon and watching church-produced audio-visual stimuli and Biblical scenes.

In repeated experiments, the scientists found that powerful spiritual feelings were associated with activation of the nucleus accumbens. The peak activity in the structure occurred between one and three seconds

before the participants reported feelings.

The researchers, who have published their findings in the journal Social Neuroscience, also observed that spiritual feelings activated brain regions associated with moral reasoning.

The findings are significant because over the past decade, studies exploring the neurobiology of religious experiences had turned up inconsistent results. Some studies had suggested that religious experiences emerge from temporal lobe structures which have also been implicated in epilepsy and schizophrenia.

"The activity in the nucleus accumbens implies that the spiritual experiences activate neural circuitry that gives pleasure to individuals," said Jamuna Rajan, a consultant neuropsychologist at the National Institute of Mental Health and Neurosciences, Bangalore, who was not associated with the US study. "It would not be surprising if similar brain activity is also observed during similar experiences of people from other religious faiths."

In 2008, neuropsychologist Uffe Schjoedt at Aarhus University in Denmark had found that prayers can activate the caudate nucleus, a structure involved in multiple brain functions, including its reward circuitry. But the caudate also contributes to language, intellect and perception.

Scientists view the increased activity in the nucleus accumbens as stronger evidence, but assert that such studies do not in any way undermine the significance of faith or religious beliefs.

"Just because prayer or spiritual thinking elicit reward in structures of the brain, it does not mean that such findings disprove the supernatural (concepts of) religious worldviews," Schjoedt told this newspaper in an email.

"It simply means that functional brain anatomy and activation can only tell us something about how the brain processes supernatural ideas."